The bearing characteristic frequencies (BCF) contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations. They are difficult to find in their frequency spectra when using the common technique of fast fourier transforms (FFT). Therefore, Envelope Detection (ED) has always been used with FFT to...

The bearing characteristic frequencies (BCF) contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations. They are difficult to find in their frequency spectra when using the common technique of fast fourier transforms (FFT). Therefore, Envelope Detection (ED) has always been used with FFT to identify faults occurring at the BCF. However, the computation of the ED is suffering to strictly define the resonance frequency band. In this paper, an alternative approach based on the Laplace-wavelet enveloped power spectrum is proposed. The Laplace-Wavelet shape parameters are optimized based on Kurtosis maximization criteria. The results for simulated as well as real bearing vibration signal show the effectiveness of the proposed method to extract the bearing fault characteristic frequencies from the resonant frequency band. Minimize

The bearing characteristic frequencies (BCF) contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations. They are difficult to find in their frequency spectra when using the common technique of fast fourier transforms (FFT). Therefore, Envelope Detection (ED) has always been used with FFT to...

The bearing characteristic frequencies (BCF) contain very little energy, and are usually overwhelmed by noise and higher levels of macro-structural vibrations. They are difficult to find in their frequency spectra when using the common technique of fast fourier transforms (FFT). Therefore, Envelope Detection (ED) has always been used with FFT to identify faults occurring at the BCF. However, the computation of the ED is suffering to strictly define the resonance frequency band. In this paper, an alternative approach based on the Laplace-wavelet enveloped power spectrum is proposed. The Laplace-Wavelet shape parameters are optimized based on Kurtosis maximization criteria. The results for simulated as well as real bearing vibration signal show the effectiveness of the proposed method to extract the bearing fault characteristic frequencies from the resonant frequency band. Minimize

This paper describes the use of Simulink Target for Real-Time Linux (ST-RTL) to control over a network a horizontal driven inverted pendulum. ST-RTL is an application developed to provide a cost-effective alternative to the expensive real-time applications that require specialised software and hardware. The application allows performing a number...

This paper describes the use of Simulink Target for Real-Time Linux (ST-RTL) to control over a network a horizontal driven inverted pendulum. ST-RTL is an application developed to provide a cost-effective alternative to the expensive real-time applications that require specialised software and hardware. The application allows performing a number of laboratory scale hard real-time control experiments, which can be remotely monitored and tuned at run-time from a second computer using a TCP/IP connection. The software packages Matlab, Simulink and Real-Time Workshop (RTW), widely used among educational institutions, are used as a controller algorithm development tool. A performance comparison with the commercial Windows based version Real-Time Windows Target has also been carried out. The conclusions will show that ST-RTL is a preferable tool since not only does it perform as well as RTWT, but it also includes remote networking capabilities to the system. Minimize

Sydnones are a class of mesoionic compounds containing a five-membered heterocyclic ring. In general, sydnone compounds are synthesized with an aromatic substutuent at the N3 position. This feature, adds to the stability of the heterocyclic ring. In the title compound {systematic name: 4-(2-bromopropanoyl)-3-phenyl-1,2,35-oxadiazol-3-ylium-5-ola...

Sydnones are a class of mesoionic compounds containing a five-membered heterocyclic ring. In general, sydnone compounds are synthesized with an aromatic substutuent at the N3 position. This feature, adds to the stability of the heterocyclic ring. In the title compound {systematic name: 4-(2-bromopropanoyl)-3-phenyl-1,2,35-oxadiazol-3-ylium-5-olate}, C11H9BrN2O3, the aromatic substitutent is an unsubstituted phenyl ring. The sydnone ring is almost planar, with a maximum deviation from the mean plane of 0.023(1)Е, but is not coplanar with the phenyl ring, having a dihedral angle of 40.93(8)°. The carbonyl side chain is twisted relative to the syndone ring by 15.8(2)°. The molecules are packed in the unit cell as pairs related by an inversion center at (1, 0, 1/2). The pairs interact via -stacking, with the distance separating the centroids being 3.824(1)Е. The Br atom has two contacts, one to an N atom in a neighboring asymmetric unit with a distance of 3.346(2)Е (the sum of the van der Waals radii is 3.40Е) and a second to an H atom with a distance of 3.03Е. The contact with the H atom is perpendicular (CBr.H = 98.60°) to the CBr bond, and that to the N atom is linear [CBr.N = 169.10(5)°] to the CBr bond. The O atom of the sydnone ring is involved in two hydrogen bonds, one intramolecular with a donoracceptor distance of 3.1486(19)Е and a second that is intermolecular, with a phenyl H atom as the donor and has a donoracceptor distance of 3.346(2)Е. Minimize

Our objective was to test whether the double Ds structure correlated with Dissociation state I activity (i.e., high frequency of chromosome breakage and low frequency of reversion) in maize exhibited similar properties in tobacco. A genetic assay was established to test double Ds and related structures for their ability to cause loss of the link...

Our objective was to test whether the double Ds structure correlated with Dissociation state I activity (i.e., high frequency of chromosome breakage and low frequency of reversion) in maize exhibited similar properties in tobacco. A genetic assay was established to test double Ds and related structures for their ability to cause loss of the linked marker genes streptomycin phosphotransferase and beta-glucuronidase in transgenic tobacco. An engineered double Ds element and a simple Ds element showed behavior consistent with that of state I and state II Ds elements, respectively, as described for maize. DNA structural rearrangements accompanied marker gene loss. Dissection of the double Ds structure showed that a left end and a right end of Ds in direct orientation were sufficient for the instability observed. This result suggested that left and right ends of Ds in direct orientation can participate in aberrant transposition events, consistent with two different models for double Ds-induced chromosome breakage proposed previously. Both models predict that the inversion of a half Ds element accompanies the aberrant transposition event. Such an inversion was detected by polymerase chain reaction experiments in tobacco and maize only when Activator activity was present in the genome. Minimize

1. The extracellular pH value in the dermis of human skin (skin pH) was measured in vivo using glass micro-electrodes. They were found to be both reliable and accurate. 2. The mean value of skin pH measured in the legs of forty different volunteers was found to be pH 7.54 +/- 0.09 (S.D.). No difference in skin pH was observed between males and f...

1. The extracellular pH value in the dermis of human skin (skin pH) was measured in vivo using glass micro-electrodes. They were found to be both reliable and accurate. 2. The mean value of skin pH measured in the legs of forty different volunteers was found to be pH 7.54 +/- 0.09 (S.D.). No difference in skin pH was observed between males and females, or in different regions of the limb. 3. Local reductions in skin surface temperature in ten subjects caused an increase of pH 0.023 +/- 0.007 per degree C fall. 4. A 20 min period of tourniquet ischaemia in twenty volunteers induced a fall in skin pH of 0.13 +/- 0.05 units. 5. Hyperventilation during a 10 min period of breathing 10% O2 in N2 caused an increase of pH 0.04 +/- 0.02 in the skin of healthy subjects. 6. Skin pH fell to a value 0.02 +/- 0.02 units below normal 10 min after the hypoxic period, suggesting the presence of excess lactate. 7. Skin pH results compared well with blood gases and pH values of arterialized samples taken during hypoxia. 8. It was concluded that the system was suitable for clinical trials. Minimize

Hemopoietic precursors with the ability to differentiate into wide varieties of cell types are considered primitive, as are precursors with long-term repopulating ability. Here we study the populations of marrow precursors from which both myeloid and lymphoid lineages are descended shortly after transplantation. Surprisingly, few or none of thes...

Hemopoietic precursors with the ability to differentiate into wide varieties of cell types are considered primitive, as are precursors with long-term repopulating ability. Here we study the populations of marrow precursors from which both myeloid and lymphoid lineages are descended shortly after transplantation. Surprisingly, few or none of these precursors show long-term repopulating ability. Equal portions of a mixture of marrow cells from C57BL/6J (B6) and congenic B6-Hbbd Gpi-1a mice are transplanted into a group of recipients. Three weeks later, highly significant correlations between percentages of B6 type T cells, B cells, granulocytes, and platelets in each recipient indicate that many lymphoid and myeloid cells are descended from common precursors. After 4-6 weeks, most correlations between lymphoid and myeloid cells improve, indicating that most or all differentiated cells are descended from common precursors. The more differentiated myeloid-specific precursors found in spleen colony-forming cell assays apparently fail to contribute significantly to the differentiated myeloid cell populations tested. By using the binomial model, in which variability of the data among the recipients is inversely related to the number of precursors in the mixture, donor precursor concentrations are estimated as approximately 21 per 10(5) marrow cells after 3 weeks, falling 3-fold to 6.6 per 10(5) after 4-6 weeks. This trend continues, with higher correlations, greater variabilities, and donor precursor concentrations of 1.9 per 10(5) marrow cells after 12-14 weeks and 1.4 per 10(5) after 24 weeks. Strong increases in variances between 3 and 12 weeks after transplantation suggest that most or all of the initially active multilineage precursors are exhausted during this time period. The fact that the ability of a hemopoietic stem cell to differentiate into widely disparate lineages is not associated with long-term repopulating ability requires a change in stem cell definitions, since primitive hemopoietic stem cells have traditionally been defined by both these abilities. Minimize

1. A rapid-sampling technique was used to obtain perchloric acid extracts of cells growing in a chemostat culture, so that meaningful values for ATP content could be obtained in spite of the fact that the turnover time for the total ATP content was about 1sec. 2. For steady-state growth, it was found that, in a glucose-limited chemostat culture,...

1. A rapid-sampling technique was used to obtain perchloric acid extracts of cells growing in a chemostat culture, so that meaningful values for ATP content could be obtained in spite of the fact that the turnover time for the total ATP content was about 1sec. 2. For steady-state growth, it was found that, in a glucose-limited chemostat culture, the ATP/ADP concentration ratio was approximately constant with changes in dissolved-oxygen tensions above the critical value, but fell when the culture was grown under oxygen-limited conditions and was at a minimum in anaerobically grown cultures. The steady-state ATP content was lower in cells growing under nitrogen-limited conditions with glucose in excess than in glucose-limited cells. The steady-state ATP content was independent of growth rate at growth rates over 0·1hr.−1. 3. When the respiration rate of the cells was stimulated by lowering the oxygen tension the ATP content did not increase, indicating either an increased turnover rate of ATP or a fall in the P/O ratio. The sudden addition of extra glucose or succinate to a glucose-limited culture increased the respiration rate of the cells, but the ATP content quickly returned to the steady-state value after initial perturbations. This control over ATP content is explained in terms of regulation by adenine nucleotides of the catabolism and anabolism of glucose. An exception to this control over ATP content was found when the respiration rate was stimulated by addition of an antifoam. Minimize